Traffic on the Internet is carried using the Internet Protocol (“IP”). The most ubiquitous version of IP is version four (“IPV4”). The Internet has undergone enormous growth since the inception of the IPV4 standard, and the sheer number of networked devices is straining IPV4.
More specifically, IPV4 uses IP addresses to identify end-points on networks and each networked device has a unique IPV4 address. A serious limitation of further Internet growth under IPV4 is the limited length of the address field. Since IPV4 uses a thirty-two bit addressing scheme of the format X.X.X.X, (where X is a value between zero and two-hundred-and-fifty-five), there are about four billion possible addresses. With the astonishing growth of the Internet, however, unique IP addresses are becoming scarce. As populous countries like China and India increase their appetite for the Internet, such addresses will become more scarce. IPV6 will offer relief by adding more addresses, but the upgrade of existing infrastructure from IPV4 to IPV6 is expected to be slow.
Even with the advent of IPV6, serious limitations remain with traffic routing over the Internet. Currently, IP addresses are administered by various organizations. For example, in North America IP addresses are administered by the American Registry for Internet Numbers (“ARIN”), a non-profit membership organization established for the purpose of the administration and registration of IP addresses. (See http://www.arin.net).
Due at least in part to scarcity of IP addresses, ARIN is currently somewhat reluctant to assign IP addresses freely. As a result, Internet Service Providers (“ISP”) that have been assigned blocks of IP addresses by ARIN, and who serve subscribers across a disparate geographic area can find subscribers at opposite ends of the geographic area with IP addresses that are numerically quite close. For example, a subscriber of a first ISP located in Edmonton, Canada, could have the IP address A.A.A.A, while a subscriber of the same ISP who is located in Montreal, Canada, could have the IP address A.A.A+1.A. In other words, the IP address allocation may bear no relation to the geographic location of the subscriber. As a result, the IP addresses may not be aggregated efficiently and therefore complex routing tables and routers are maintained throughout the ISP's backbone to physically locate and deliver traffic to a computing device that is associated with a particular IP address. The resulting routing tables can become extremely bloated due to the need to send more specific routing announcements at each router in an attempt to accommodate the inefficient assignment of IP addresses.
Such suboptimal IP address assignments affect how traffic traverses the internet. When the ISP announces their network to other providers primarily via Exterior gateway protocol, other providers expect and may enforce some sort of IP address aggregation. If the aggregation occurs. The ISP may lose the ability to control the path the return-traffic may take to arrive to a particular computing device. This lose of route granularity caused by address aggregation may lead the second ISPs carrying the return-traffic to do “hot potato routing” (or sometimes known as “deflection routing”). Hot potato routing occurs where the second ISP does not receive path preferences instructions from the receiver of the return-traffic (the first ISP) or may not want to incur the cost of carrying traffic destined to subscribers of the first ISP. The second ISP will then try to dump the traffic onto first ISP at the closest or cheapest cost junction point For example, assume that the first ISP has junctions to a second ISP in Chicago and in Seattle for passing traffic between the two ISPs. Assume also a second ISP has traffic that originates in Florida which is destined for the Montreal subscriber having the address A.A.A+1.A. In normal situations the best and shortest path for the second ISP to deliver a packet to the first ISP may be the Chicago junction taking the least physical distance. With hot potato routing, the second ISP may dump the traffic to the junction between the two ISPs in Seattle that gets the traffic into the first ISP at a lower cost. This behaviour results in bigger issues like asymmetric routing and reduced performance due to the added distance a packet may take to reach the intended destination.